A Canadian citizen seriously injured in Monday's deadly bus hijacking in the Philippines was flown from Manila to Hong Kong Thursday.

Jason Leung, 18, suffered a serious head wound during the deadly shooting rampage, after a ex-policeman armed with an M-16 assault rifle took control of a busload of tourists. His father, Ken Leung, 58, and two sisters, Jessie, 14, and Doris 21, were among the eight killed when their hostage taker began firing.

Leung's mother, Amy Ng, was unhurt in the shooting and was with her son on the trip back to Hong Kong.

Leung was not expected to be moved from a Manila hospital for some time, CTV's Beijing Bureau Chief Ben O'Hara-Byrne reported Thursday, but a Hong Kong neurosurgeon deemed him stable enough to return to the city.

"The decision to bring him back was a very difficult one but his mom really wanted to get back home," O'Hara-Byrne told CTV's Canada AM. "Doctors so far say it is a tricky situation, but they are hopeful he will recover."

The Leung family members were dual Canadian-Chinese citizens, residing in Hong Kong. Jason and Doris were attending school in the Toronto-area and were in the Philippines with their family for a vacation.

In Hong Kong, citizens observed three minutes of silence for the victims of Monday's bus hijacking.

"It was a very sombre morning in Hong Kong, flags were raised then lowered, across the city three minutes of silence were observed for the hostages that died or were injured," O'Hara-Byrne said.

‘Someone will pay'

The police response to the hijacking has been the subject of tremendous criticism, both within the Philippines, and aboard.

On Thursday, Philippine President Benigno Aquino III, vowed "someone will pay" as senators began drilling senior police officials on the deadly hostage taking.

"What happened should not happen again," he said. "Someone failed, someone will pay."

While the president stopped short of directly blaming the police, he admitted there were many failures involved.

In the Senate investigation, Manila police chief Rodolfo Magtibay said he ordered police to storm the bus after shots were heard inside following the breakdown of negotiations with the hostage taker.

Magtibay has taken a leave of absence and four senior members of the assault team have been relieved of their duties pending the investigation.

Police admitted they were ill-prepared for the situation, lacking equipment such as a ‘flash-bang' grenade, which can be used to stun a hijacker.

The hijacker, Rolanda Mendoza, 55, was killed by police after he opened fire on the busload of tourists. He had been fired under a cloud of criminal suspicion and was demanding his job as a police officer back.

The daylong standoff with Mendoza was carried on live television, and shocked many in Hong Kong, an affluent city unused to violent crime.